UGI tests new system to detect gas leaks

Utility's pilot program is part of a settlement over Allentown's 2011 blast.

February 08, 2014|By Scott Kraus, Of The Morning Call

On a frigid February night three years ago, natural gas leaking from a cracked cast-iron distribution line caused a massive explosion that lit up the sky above Allentown, killed five people and leveled eight row homes at 13th and Allen streets.

A cold-weather leak survey crew that had been in the area the day before did not detect any leaks in the pipe, which dated to 1928. No one in the area reported smelling gas before the explosion.

This winter, UGI Utilities is testing new gas leak detection technology on the streets of Allentown, a pilot project it was required to conduct as part of its $500,000 settlement with the Pennsylvania Public Utility Commission over the deadly blast.

The new technology, strapped to the front of an ordinary Nissan pickup truck and hooked up to a computer, uses infrared light to detect escaping natural gas and pinpoint the location of leaks. It is more sensitive than the standard flame-ionization technology now used by UGI, and isn't triggered by other flammable gases.

"It will detect any level of methane down to as little as a tenth of a part per million," said John Sullivan, regional sales manager for Sensit Technologies of Valparaiso, Ind., which produces the technology that was developed by the Gas Technology Institute and introduced in 2010.

UGI is the first gas company in Pennsylvania to deploy the new technology, which can find and pinpoint a wide range of leaks and "streamlines leak survey and detection operations, promising to help the natural gas industry reduce operation costs," according to the institute.

The PUC approved UGI's plan to issue a request for proposals for the pilot leak detection program in June. After issuing the request, UGI selected Sensit to provide the detection technology and Precision Pipeline Solutions of New Windsor, N.Y., to supply the technicians for the pilot.

PUC staff investigators had wanted more, urging the commission to require UGI to engage in continuous leak monitoring, submit monthly progress reports and repair even minor leaks in Allentown in addition to the company's promise to launch a pilot program.

Following PUC rules, UGI steps up leak-detection patrols in the winter, monitoring its cast-iron pipes once every two weeks with flame-ionization-detection teams between Jan. 1 and March 21. The pilot program deploys additional teams between Nov. 1 and March 31 using the new technology.

Flame-Ionization detectors pass air samples through a hydrogen flame to test for combustible gas. The new infrared system uses a light sensor that is triggered when methane molecules deflect an infrared beam. The new technology is easier to calibrate and better at pinpointing leaks, according to its creators.

This winter, both types of detectors have been deployed on Allentown's streets, allowing UGI to compare their effectiveness, said Hans G. Bell, UGI's vice president of engineering and operations support.

"UGI is looking at the applicability of the technology as the deciding factor of what we need to do," he said. "We hold safety first, above costs."

When the pilot is complete, UGI will submit a report on the results to the PUC.

The results will be shared with other utilities with the goal of improving leak detection across the state, PUC spokeswoman Jennifer Kocher said. The PUC is especially interested in whether the equipment will do a better job picking up smaller leaks that can be scheduled for repair, or monitored.

Existing leak detection equipment is plenty sensitive, but gas companies don't always want workers to find every leak because fixing them can be expensive, said gas safety expert Mark McDonald of Boston-based NatGas Consulting. Since not all leaks are imminently dangerous, some gas companies would prefer not to catch smaller leaks they consider minor, he said.

"Flame-ionization detectors are very sensitive and will pick up any gas leak, in my experience … unless the operator turns the sensitivity scale down," he said. "This will end up in not every gas leak being found."

McDonald said in his own experience working the natural gas industry, he encountered situations in which he or co-workers were told to "just get the big ones."

UGI wants its workers to find every leak, with no exceptions, spokesman Joe Swope said.

"UGI classifies and addresses all leaks detected on its system no matter how small," he said. "Hazardous leaks are repaired immediately, non-hazardous leaks are monitored and scheduled for repair, and minor leaks are carefully monitored."

The winter poses a particular risk to old underground utility pipes because water in the ground expands and contracts as temperatures rise and fall around the freezing mark. Gas leaks are especially dangerous in the winter because frozen ground can prevent escaping gas from reaching the surface, where it can dissipate harmlessly. Instead, the gas can travel beneath the ground until it makes its way into buildings, where it can collect and ignite.